Friction transmission mechanism



an. 2l, 1930.

w. A. READY FRICTION TRANSMlSSION MECHANISH Filed 001,.' 36. 1922Patented Jan. 2l, 1930 wnLIAM A. READY, or BROOKLINE, nassacmrsn'r'rsFRICTION TRANSMISSION 'MECEANISM Application led Qctober 26, 1922.Serial No. 597,014.`

This invention relates to a friction transmission mechanism particularly'adapted for use in connection with rotating the movable part of a radioor like instrument and has for its object to provide a frictionmechanism embodying the principle of the well known v planetary gearingbut in a manner to eliminate the customary back-lash which is lpresentwhere gears are employed, and to permit the contacting surfaces to slipone upon the other if for any reason the driven memberV is obstructed. f

Another object of the invention is to construct a device through themedium of which a member which normallyI constitutes the,

driven member is rotated at a much slower speed than the driving member,the construction being such, however, that if it is so desired,the-operation of the mechanism may be reversed and the member whichnormally performs the functions of a driving member will constitute thedriven member, in which,

event the latter is rotated at a muchY faster speed than its drivingmember.

f' The invention consists in the combination and arrangement of partsset forth in the following specifcation and particularly pointed out inthe claims thereo Referring to the drawings:

Figure 1 represents a front elevation of a portion of the mechanismembodying the invention.

Fig. 2 representsa central, vertical section taken on the line 2--2 ofFig. 1, the same being illustrated upon an enlarged scale.

tl t Flg 3 1S a transverse Sec lon aken on he portion of which projectstherethrough, 1s a plate 19 to which a stationary friction memline 3--3of Fig. 2.

Like numerals refer to like parts throughout the several views of thedrawings.

In the drawings, A represents a rotatable driving member embodyingtherein a driving shaft 5 at one end of whicha handle 6 is rigidlyfastened in any desirable manner. The handle 6 is preferably constructedof suitable insulating material and has a metal bushing 7 located withina recess 8 formed therein, said bushing being vmounted upon said shaft.The shaft 5 has a ange 9 formed v0 integial therewith which is providedwith a bevelled end surface 10 extending therearound.

Rotatably mounted upon the opposite end portion of `the shaft 5 fromthat at which the handle 6 is located is a driven member 55 B embodyingtherein a flanged member 11, the bore of which is lined with insulating-material 12. A shaft 13 constituting a driven shaft is secured in anySuitable manner within the member 11 and is'entirely/insulated 60therefrom and from the driving shaft 5 by the insulating material 12.The longitudinal median. lines of the-driving shaft 5 and driven shaft18 are coincident.

A plurality of studs 14 preferably three 65 in number, are rigidlysecured in the member 11, preferably by being riveted at one end thereofto said member and rotatably mounted upon each stud 14 is a frictionwheel 1 5 provided with oppositely disposed` bevelled 7o end surfaces151 and 152, theformer overlapping and contacting with the bevelled endsurface 10 of the fiange 9. A'friction collar 16 is slidably mountedupon the driving shaft 5 and is provided with a bevelled surface 17 75extending therearound which contacts with the bevelled surfaces 152 ofthe discsof wheels 15. A spring 18 surrounds the shaft 5 and acts toalways force the collar 16 into contact with the friction wheels 15,said collar conso tacting with equal pressure with each, of said wheels,the end surfaces 151 and 152of the latter contacting with the bevelledendv surfaces 10 and 17 of the flange 9 and collar 16 res ectively.

. cated adjacent to the driven member B, a

ber 20 is. secured in any desirable manner. The plate 19 and stationaryfriction member 90 20 are securedpsimultaneously by screws 21 to a frame22 of any suitable character but preferably constructed of insulatingmaterial, and said frame constitutes a. support for the entiremechanism. The stationary friction' 95 member 20 has an annular flange23 formed integral therewith which is provided with a bevelled' surfacel, 24 extending therearound against which the friction wheels 15contact. A'floating friction ring 25 is loosely mounted 100 within thefriction member 20, being located upon the opposite side of the frictionwheels 15 from the flange 23 and is provided with a bevelled surface 26extending therearound which contacts with the bevelled surfaces 151 ofthe friction wheels 15. A plurality of inwardly projecting lips 27formed integral with the plate 19 and constituting springs Contactwith-the ring 25'and act to always force the latter against the frictionwheels 15 and the opposite corners of the latter are gripped between thebevelled surfaces 24 and 26 of the iange 23 and ring 25 respectively. Adial 28 provided with suitable graduations 29 is riveted to the studs14; and is, therefore, rotatable in unison with 'the driven member B.The dial 28 indicates the position of thevdriven member and is formed insuch a manner that'it encloses the mechanism exclusive of the handle 6at the front thereof and therefore also constitutes a shieldfor therotating and revolving parts of the mechanism. A mark 30 provideduponthe frame 22 is utilized in conjunction with the graduations 29 toindicate the movement of the dial 28.

The general operation of the mechanism which, in its present embodimentis adapted to be connected through the medium of the shaft 13 to a radiocondenser or other rotary adjustable circuit tuning device in order toadjust the rotor thereof relatively to the stator and between which itis desirable to obtain a very fine adjustment, is as follows z-l Thehandle 6 when rotated in the direction of the arrow a in Fig. 1 causeseach of the friction wheels 15 to be rotated in the direction of thearrows b in Fig. 3 by being gripped between the bevelled surfaces 10 and17 of the.

'flange 9 and collar 16 respectively but owing .to the fact that saidwheels 15 are also'gripped of. speed as compared to the speed of thehan- I dle 6. The driven shaft 13 fast in the member 11 and the dial 28also fast to said member all travel at the same rate of speed as themember 11 and in the same direction. In the mechanism illustrated, thevarious parts kare sov proportioned that the ratio of speed of thehandle 6 as compared to the speed ofthe drivenv shaft 13 is as five toone and a very slight movement may therefore be given to s the shaft13'if the handle 6 is turned slowly.

It is evident that if itis so desired, theoperation of the mechanism maybe reversed without depart-ing from the spirit of the invention, inwhich event the shaft 13 which normally constitutes thedriven shaft,will uconstitute the 'driving shaft and the shaft 5 will constitute 4thedriven shaft. At such times the ratio of speed of the driving shaftv ascompared t0 the speed of the dnven shaft is not necessary to employ adial to indicate.

the position of the driven member, the graduations 29 may be omitted andthe member 28 minus said graduations may still be utilized to constitutea shield to protect the moving parts ofthe mechanism, or, said member 28maybe omitted and the mechanism enclosed in a suitable stationaryshield. f

lVhile I have illustrated and described a preferred embodiment of myinvention, do not wish to be limited thereby and reference is made tothe following claims to indicate the scope of my invention.

I claim:

1. A transmission mechanism comprising, in combination, a drivingmember, a driven member, friction wheels rotatably mounted upon one ofsaid members and having frictional engagement with the other of saidmembers, a dial fast. to one of said members, a stationary frictionmember and floating yielding means to hold said Wheels in frictionalengagement with said stationary friction member and co-operating withthe latter to pinch said wheels therebetween.

2. A transmission mechanism comprising, in combination, a drivingmember, a driven member, friction wheels rotatably mounted upon one ofsaid members'and having frictional engagement with the other of saidmembers, a stationary annular friction member engaging said frictionwheels upon one side thereof and a floating ring yieldingly engagingsaid friction wheels upon the other side thereof.

3. A transmission mechanism comprising, in combination, a drivingmember, a driven member, friction wheels rotatably ymounted upon one ofsaid members and having frictional engagement with the otherof saidmembers, a stationary annular friction member engaging said friction'wheels upon one side thereof, a floating ringyieldingly engagingsaidfriction wheels upon the other side thereof and a friction collaralso yieldingly engaging said friction wheels.

4. A transmission mechanism comprising, in combination, a drivingmember, 'a driven member, friction wheels rotatably mounted upon one ofsaid members and having frictional engagement with the other of saidmembers, a dial fast to one of said memj bers and rotatable in unisontherewith, a

ber, a stationary annular friction member. engaging said friction wheelsupon one side thereof, a floating ring yieldingly engaging said frictionwheels upon the other side thereof anda friction collar mounted uponsaid driving member and yieldingly engaging said friction wheels.

6. A transmission mechanism comprising,

- in combination, a drivingshaft, a handle of insulating material fastto said shaft, a member rotatably mounted upon said driving shaft, ashaft mounted in said member and insulated therefrom, friction wheelsrotatablyv mounted upon said member and having frictional engagementwith said driving shaft` a dial fast to said member and rotatable inunison therewith, a stationary annular friction member engaging saidfrictionfwheels upon one side thereof, a ring yieldingly engaging saidfriction wheels upon the other side thereof, a friction collar mountedupon said driving shaft and means to force said collar into engagementwith said friction wheels.

7. A transmission mechanism comprising, in combination a driving shaftprovided with a bevelled surface thereon, a handle fast to said shaft, arotatable driven member, frictional wheels rotatably mounted upon saiddriven member and provided with bevelled surfaces thereon, one of saidsurfaces having frict-ional engagement with the bevelled surface of saiddriving shaft, a dial m hand.

y WILLIAM A. READY.

fast to said driven member and rotatable in unison therewith, astationary annular friction member provided with a bevelled surfacethereon having frictional engagement with the bevelled surface of saidfriction wheels upon oneside thereof, a ring provided with a bevelledsurface and yieldingly engaging the bevelled surface of said frictionwheels upon the other side thereof, a friction collar mounted upon saiddriving shaft and provided with a bevelled surface thereon and means toforce said collar'into engagement with said friction wheels, thebevelled surface of the former contacting with a bevelled surface of thelatter.

8. A variable indicating mechanism for securing and indicating the fineadjust-ment of a radio instrument located behind the panel of a radioset, said indicating mechatnism including a hub for detachableengagement with a shaft of the instrument to bev adjusted, an inscribeddial exposed at the front of the panel and operatively connected withsaid hub to indicate the degree of rotation thereof, a hand operatedldriving member comprising a knob located in front of the panel, asha-ft extending from said knob and friction operated means connectedbetween the hub and hand operated shaft whereby when said knob isrotated said friction means will4 transmit motion tothe hub andinscribed dial, said friction operating

